Design and Construction of a 2.45 GHz Microwave Electrothermal Thruster

Abstract

A microwave electrothermal thruster (MET thruster) has been constructed, consisting of a microwave plasma chamber 12 cm long and 8 cm in inner diameter and a micronozzle 10 mm long with 1 mm in diameter. The microwave plasma is produced by 2.45 GHz microwave frequency at a power of 1 kW, and the feed gas is Ar at a pressure of 10^-3mTorr. Microwave energy is transmitted into the cavity and electrons sre connected to the wave's electric field. Thus, the electrons are accelerated by microwave electric fields. Microwave plasma discharge is formed based on the interaction of electrons with neutral gas particles. Then, the plasma acts as a resistive load and absorption of microwave energy, raises the temperature of the gas or plasma. Gas heating increases the gas pressure and is released through the nozzle. The plasma density and electron temperature are 2.35×〖10〗^17 m^(-3) and 1.2 eV, respectively. The thrust and specific impulse are 10 mN and 100 s.